Various vehicles or implements that are configured for negotiating sloped terrain (such as hillside combines, excavation and construction equipment, military vehicles, etc.) may use leveling or tilt systems to level at least a portion of the vehicle (such as an operator cabin, a grain storage bin, etc.) while traversing the sloped terrain. Leveling systems cause a portion of the vehicle to be tilted to produce the leveling desired. For example, one or more axles of a vehicle may be tilted, with one end of the axle extended away from the body of the vehicle while the other end of the axle is more or less fixed or contracted toward the body of the vehicle. Such leveling systems often include techniques for sensing the slope of the terrain and then compensating for the slope by leveling portions of the vehicle while the vehicle is on the slope.
Many leveling systems have sensors that use gravity for sensing the slope of terrain. These sensors are generally not able to distinguish gravity from other forces, such as centrifugal force, for example, and may give inaccurate information as a result. For example, common techniques for sensing a slope include the use of accelerometers, liquid capacitive devices, electronic devices, electrolytic devices, devices that include a gas bubble in a liquid, and pendulum devices. Each of these types of sensing devices uses gravity to detect slope, and may be affected by other forces (e.g., centrifugal force, etc.) as well.
For example, when a vehicle turns a corner, the centrifugal force acting on the vehicle can be felt by a leveling sensor (e.g., clinometer, tilt meter, etc.), causing the leveling sensor to output an erroneous signal indicating that the vehicle is on a slope, even when the vehicle is on level terrain. This effect may be compounded with increased cornering speeds and/or with tighter turning circles. An erroneous signal from the leveling sensor can cause a vehicle such as a hillside combine, for example, to tilt the cabin, storage bin or whole machine while the vehicle is turning a corner on level terrain.